when revving my car..the tach will only go to 5 grand...then it bounces back to 1 then back up to 5..this only happens when i use my Jdmshit jumper and a p72 ecu...it does not do this when using the stock p75(ls) ecu...but under 5 grand the tach works fine...............?

 

somebody help this guy out...cause i'm having the same problem...some people say the distributor is bad....anybody have more info on this??

 

usually when aftermarket tachs bounce all over the place, they can be fixed by doing this:

take distributor cap off. find your ignitor. three wires are connected to it. they are usually loose. take them off, put a little dialectric grease on the plugs, put them back on and squeeze them tight with a pair of pliers.

 

hey guys if its after market tach check the wire that runs from the tach to the distributor the wire might be loose it happened on my car the wire is blue on my car

 

Yeah, check in the distributor... boucing tach is normally a loose or frayed wire... OR a ignitor/ECM kicking out.

Does the car buck at all ? (curious)